Equilibration with extra safeguard

Introduction

This section contains an example of how a Watch instruction for extra safeguard can be inserted into a method.

Example instruction

This is an example instruction as it would be presented in the Text pane:

0.00 Block EQUILIBRATE

(Equilibrate)

0.00 Base SameAsMain

0.00 Block COND_LESS_THAN

(Cond_less_than)

0.00 Base SameAsMain

0.00 Watch_Cond Less_than, 5 {mS/cm} END_BLOCK

6.00 Message “Low conductivity not reached”, Screen, “No sound”

6.00 Pause INFINITE {Minutes}

6.00 End_Block

0.00 Block COND_STABLE

(Cond_stable)

0.00 Base SameAsMain

0.00 WatchPar_Cond 0.500 {mS/cm}, 2 {mS/cm}

0.00 Watch_Cond Stable_Baseline, 5 {Minutes}, END_BLOCK

10.00 Message “Conductivity not stable”, Screen, “No sound”

10.00 Pause INFINITE {Minutes}

10.00 End_Block

0.00 End_Block

Note: If you are not using ÄKTA instruments, a delay should be added after the Hold/Pause instruction so that the following instruction will not be executed simultaneously with the Hold/Pause instruction.

This is what happens

The table below describes what happens in the above example:

Stage

Description

1

The column is equilibrated until the conductivity is below 5 mS/cm.

2

If this value is not reached within 6 column volumes, the method is paused and a message is displayed.

3

Equilibration of the column is continued until the conductivity value is “stable” (allowed to vary by max. ±2 mS/cm) over a period of at least 5 minutes.

4

If this condition is not met within 10 column volumes, the method is again paused.

Note: At each pause, the operator can decide whether to continue or abort the run.

2005-06-15